Hummer H1 (2006+). Manual - part 186

4-24

Cooling System

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11. Install the large center idler pulley.

12. Install the serpentine drive belt.

13. Fill and bleed the cooling system. See cooling system service for proper filling and bleeding procedure.

14. Connect the battery.

Figure 4-19:   Water Pump

AUXILIARY WATER PUMP

Removal

1.

Drain the cooling system.

2.

Disconnect the batteries and remove the battery tray.

3.

Remove the auxiliary water pump connector.

4.

Remove the two hose clamps, inlet and outlet hoses from the auxiliary water pump (Figure  4-20).

Installation

1.

Install the inlet, outlet hoses on the auxiliary water pump and secure with the two hose clamps (Figure  4-20).

2.

Install the auxiliary water pump connector.

3.

Install the battery tray and the batteries.

4.

Fill and bleed the cooling system. See cooling system service for proper filling and bleeding procedure.

WATER PUMP

GASKET

ENGINE WATER

PIPE

WATER PIPE

GASKET

11-1-05

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 Cooling System  4-25

5745804

Figure 4-20:   Auxiliary Water Pump

AUXILIARY

WATER PUMP

BYPASS

VALVE

UPPER

RADIATOR HOSE

INLET

HOSE

OUTLET

HOSE

HOSE

CLAMP

4-26

Cooling System

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SERPENTINE BELT REPLACEMENT

Removal

1.

Insert the square lug of special tool EN- 47913 in the belt tensioner. Then move the tensioner counterclockwise to loosen the
belt (Figure  4-21).

2.

Remove the belt from the pulleys (Figure  4-22).

Installation

1.

Insert the square lug of special tool EN- 47913 in the belt tensioner and move the tensioner counterclockwise and position the
serpentine belt on the pulleys as shown (Figure  4-22).

2.

Release the belt tensioner. Tensioner will automatically set the belt tension when it is released.

Figure 4-21:   Serpentine Belt Tensioner Location

Figure 4-22:   Serpentine Belt Routing 

SERPENTINE

BELT

BELT TENSIONER 

AND PULLEY

CRANKSHAFT

PULLEY

GENERATOR

PULLEY

TENSIONER

PULLEY

A/C COMPRESSOR

OR IDLER PULLEY

SERPENTINE

BELT

POWER

STEERING

PUMP

PULLEY

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 Cooling System  4-27

5745804

Figure 4-23:   Automatic Belt Tensioner

Automatic Belt Tensioner and Belt Length Scale

A serpentine belt drives the water pump which pumps the coolant through the cooling system. Proper belt tension must be main-
tained at all times for the proper operation of the cooling system. This is accomplished by an automatic belt tensioner located at the
front of the engine behind the coolant surge tank (Figure  4-23). The amount of belt stretch may be determined with the scale lo-
cated on the arm or the belt tensioner. If the single line falls outside of the dual line parameters, replacement is required.

Inspection of a multiple ribbed serpentine belt may reveal cracks in the belt ribs. These cracks will not impair the belt performance
and are not a basis for belt replacement. If excessive cracking is noted or any belt ribs are missing, the belt should be replaced.

FAN AND CLUTCH ASSEMBLY SERVICE

Removal

1.

Remove the geared fan drive assembly (Figure  4-26).

2.

Remove the bolts attaching the fan clutch to the GFD.

3.

Remove the bolts attaching the fan to the fan clutch.

Installation

4.

Slide the fan onto the clutch and tighten the bolts to 15-20 lb-ft (20-27 N•m).

5.

Install the fan and clutch assembly on the GFD (Figure  4-26).

6.

Install the geared fan drive assembly.

GEARED FAN DRIVE (GFD) ASSEMBLY SERVICE

Geared Fan Drive

CAUTION: If the fluid level is checked when the unit is hot, some of the expanded fluid will run out and create a low fluid condi-
tion.

The fluid level in the reservoir must be checked every 6,000 mi (9,700 km) or semiannually, whichever occurs first and topped off
using HUMMER H1 Synthetic Gear Lube 75W-90 with friction modifier. Remove the fill plug when the unit is cold and ensure
that the fluid is even with the bottom of the fill plug hole (Figure  4-24). The coupler shaft CV joints must be greased every 6,000
mi (9,700 km) or semiannually, whichever occurs first with a multipurpose, NLGI-LB grade chassis grease. The coupler shaft has
a CV joint at the GFD end and one at the engine crankshaft end. Each CV joint contains two grease zerks, although only one zerk
needs to be greased per joint. The second zerk is used to give an optional location depending on the position of the shaft when the
engine stopped. This should lessen the need to bar the engine over to gain access to the zerks. Grease should be applied, using a low

BELT TENSIONER

11-1-05